BRPOPLPUSHsourcedestinationtimeout

Available since 2.2.0.

Time complexity: O(1)

BRPOPLPUSH is the blocking variant of RPOPLPUSH.
When source contains elements, this command behaves exactly like RPOPLPUSH.
When used inside a MULTI/EXEC block, this command behaves exactly like RPOPLPUSH.
When source is empty, Redis will block the connection until another client
pushes to it or until timeout is reached.
A timeout of zero can be used to block indefinitely.